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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1025 AM EST FRI FEB 27 2015

.UPDATE...
NEAR TERM SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 303 AM EST FRI FEB 27 2015

HIGH PRESSURE IS EXPECTED ACROSS THE AREA THROUGH SATURDAY. A 
FRONTAL SYSTEM IS EXPECTED TO MOVES THROUGH THE AREA FRONT SATURDAY 
NIGHT INTO SUNDAY NIGHT. A STRONGER LOW PRESSURE SYSTEM MAY AFFECT 
THE AREA TOWARDS THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1025 AM EST FRI FEB 27 2015

CANCELLED WIND CHILL ADVISORY AS WIND CHILLS ARE NO LONGER REACHING 
ADVISORY CRITERIA.  

OTHERWISE...SATELLITE INDICATES MOSTLY CLEAR SKIES WERE ACROSS MOST 
OF THE AREA.  RUC MODEL SOUNDINGS INDICATE CU MAY INCREASE THIS 
AFTERNOON CAUSING SKIES TO BECOME PARTLY CLOUDY.  

RUC SOUNDINGS INDICATE HIGHS FROM MIDDLE TEENS NORTH TO AROUND 20 
SOUTH WHICH IS CLOSE TO CURRENT FORECAST AND A LITTLE WARMER THAN 
MOST MOS GUIDANCE.  THIS SEEMS REASONABLE.  THERE SHOULD BE A LOT OF 
SUNSHINE AT LEAST THROUGH MID DAY AND THEN A LITTLE MORE CLOUDINESS 
THIS AFTERNOON.  REST OF NEAR TERM SEEMS TO BE ON TRACK.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 303 AM EST FRI FEB 27 2015

DRY CONDITIONS EXPECTED TONIGHT AND SATURDAY AS SURFACE HIGH 
PRESSURE GRADUALLY SHIFTS OFF TO THE EAST. MAIN ITEM OF INTEREST 
DURING THIS PERIOD IS A SHORT WAVE TROUGH THAT IS EXPECTED TO DROP 
SOUTHEAST ACROSS THE GREAT LAKES SUNDAY NIGHT. THE SURFACE 
REFLECTION ASSOCIATED WITH THIS FEATURE DOESN/T LOOK TOO 
IMPRESSIVE...BUT MODELS SUGGEST A 40 KT LOW LEVEL JET ASSOCIATED 
WITH THIS FEATURE...WHICH SHOULD PROVIDE QUITE A BIT OF LIFT.

WILL BRING IN HIGH POPS BY LATE SATURDAY NIGHT AND SUNDAY BASED ON 
ABOVE REASONING...WITH POPS TAPERING OFF SUNDAY NIGHT AS MAIN LIFT 
PUSHES OFF TO THE EAST. OPERATIONAL MODELS SUGGEST MAINLY SNOW OVER 
ABOUT THE NORTHERN HALF OF THE FORECAST AREA...WITH MORE OF A MIX 
OVER THE SOUTHERN HALF...WHICH GOES ALONG WITH THE PREVIOUS 
FORECAST. HOWEVER...THE ENSEMBLES SUGGEST A STRONGER PUSH OF WARM 
AIR IS POSSIBLE...WITH POTENTIAL FOR RAIN AS FAR NORTH AS THE 
NORTHERN ZONES BY SUNDAY. CAN/T RULE OUT THESE SOLUTIONS GIVEN THE 
STRENGTH OF THE LOW LEVEL JET. FOR NOW...WILL STICK WITH THE 
PREVIOUS FORECAST REGARDING PRECIPITATION TYPES AND MONITOR THE 
TRENDS. SEVERAL INCHES OF SNOW ARE POSSIBLE WITH THIS 
SYSTEM...ESPECIALLY OVER THE NORTHERN ZONES.

BASED ON LOW LEVEL THICKNESSES...THE GFS MOS TEMPERATURE GUIDANCE 
FOR TONIGHT AND SATURDAY LOOK A LITTLE COLD. WILL BUMP UP THE 
GUIDANCE A FEW DEGREES IN THOSE PERIODS. THE GUIDANCE HIGHS ON 
SUNDAY LOOK TOO WARM CONSIDERING EXPECTED PRECIPITATION...SO WILL 
NUDGE THOSE NUMBERS DOWN ABOUT A CATEGORY.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 258 AM EST FRI FEB 27 2015

ACTIVE PATTERN CONTINUES THROUGH THE FIRST HALF OF NEXT WEEK AS 
PIECES OF ENERGY ALOFT EJECT OUT OF THE TROUGH OVER THE WESTERN U S 
FOLLOWED BY THE TROUGH AXIS ITSELF MOVING EAST INTO THE REGION BY 
THE END OF THE PERIOD. HIGH CONFIDENCE IN A SIGNIFICANT WEATHER 
IMPACT FOR CENTRAL INDIANA AND THE OHIO VALLEY MONDAY NIGHT THROUGH 
WEDNESDAY.

STRONG HIGH PRESSURE ARRIVES IN THE WAKE OF THE LATE WEEKEND SYSTEM 
FOR MONDAY...AND SHOULD SERVE TO GIVE THE REGION A BREATHER BETWEEN 
WEATHER SYSTEMS ON THE ORDER OF 18 TO 24 HOURS. SURFACE WAVE SET 
TO SPIN UP OVER THE CENTRAL ROCKIES MONDAY NIGHT AS ENERGY EJECTS 
OUT FROM THE PARENT TROUGH. THIS FEATURE WILL SWING E/NE AND TRACK 
QUICKLY INTO THE REGION BY TUESDAY EVENING AND BRING WITH IT A 
PLETHORA OF MESSY PROBLEMS FOR CENTRAL INDIANA. RIDGING DEVELOPING 
DOWNSTREAM OF THE TROUGH SUPPORTS MORE AMPLIFIED FLOW WITH THE 
SURFACE WAVE TRACKING THROUGH OR NORTH OF THE FORECAST AREA. OP GFS 
SHOWING ITS USUAL PROGRESSIVE BIAS IN THE MID RANGE IN BRINGING 
PRECIP IN TOO QUICKLY...ESPECIALLY CONSIDERING THE STRENGTH OF THE 
DEPARTING HIGH. LIKE THE LOOK OF THE ECMWF/GGEM WHICH DELAYS MOST 
PRECIP UNTIL AFTER MIDNIGHT MONDAY NIGHT. 

WARM ADVECTION WILL ALREADY BE ONGOING WHEN PRECIP STARTS...AND 
EXPECT PRECIP TYPE ISSUES FROM THE GET GO WITH A GROWING LIKELIHOOD 
THAT FREEZING RAIN IS THE PREDOMINANT PRECIP TYPE INTO TUESDAY 
MORNING. THE REFRESHED SNOWPACK COURTESY OF THE WEEKEND STORM WILL 
BE A SIGNIFICANT FACTOR IN DURATION OF FROZEN PRECIP AS THE NEAR 
SURFACE/GROUND TEMPS WILL LAG THE LOW LEVEL TEMP RISES. MODEL 
THERMAL PROFILES ARE ALREADY SUGGESTIVE THAT IT MAY TAKE UNTIL 
MIDDAY TUESDAY IN SOME PORTIONS OF THE REGION TO WARM SUFFICIENTLY 
FOR ALL RAIN. IF THE IMPACT OF THE SNOWCOVER IS UNDERMINED BY THE 
MODELS WHATSOEVER...THE ICING POTENTIAL COULD BE EVEN MORE 
SIGNIFICANT. DO NOT EXPECT TO HAVE A GOOD HANDLE ON THIS UNTIL LATER 
IN THE WEEKEND. 

WHILE THE ICING THREAT IS A GROWING ISSUE...AN EXTENDED PERIOD OF 
HEAVY RAIN OVER A FROZEN GROUND AND SNOW COVER POSES EVEN GREATER 
CONCERNS. COPIOUS AMOUNTS OF MOISTURE WILL BE DRAWN NORTH INTO THE 
REGION AHEAD OF THE APPROACHING SURFACE WAVE TUESDAY AND TUESDAY 
NIGHT. PRECIP WATER VALUES ARE PARTICULARLY ALARMING...MAXING OUT 
BETWEEN 1.25 AND 1.50 INCHES TUESDAY EVENING. THESE LEVELS WOULD 
PLACE THE REGION NEAR AND ABOVE THE 99TH PERCENTILE FOR 
CLIMATOLOGICAL PRECIP WATER VALUES IN MARCH. POTENTIAL FOR 
CONVECTIVE ELEMENTS TO THE PRECIP AS WELL AND MAY NEED TO ADD AN 
ISOLATED THUNDER MENTION INTO THE FORECAST FOR TUESDAY 
AFTERNOON/NIGHT. 1-2 INCHES OF RAINFALL CERTAINLY LOOK PLAUSIBLE AND 
WITH MOST OF THIS BEING CONVERTED TO PURE RUNOFF WITH THE FROZEN 
GROUND...FLOODING CONCERNS ARE VALID. FRONTAL BOUNDARY SHOULD 
FINALLY MOVE EAST WEDNESDAY WITH PRECIP ENDING LATE DAY...LIKELY AS 
A RAIN/SNOW MIX. MUCH COLDER AIR WILL THEN RETURN FOR THE END OF THE 
WEEK.

STILL PLENTY TO HASH OUT AND THE WEEKEND WINTER STORM WILL HAVE SOME 
SAY IN HOW THIS ALL TRANSPIRES. AS STATED ABOVE THOUGH...CONFIDENCE 
IS HIGH IN SIGNIFICANT WEATHER IMPACTS FOR CENTRAL INDIANA MONDAY
NIGHT THROUGH WEDNESDAY...WITH ICING...HEAVY RAIN AND FLOODING ALL
POTENTIAL CONCERNS. ENCOURAGE HOOSIERS TO STAY ABREAST OF THE
FORECAST OVER THE NEXT FEW DAYS.

&&

.AVIATION /DISCUSSION FOR 271500Z TAF UPDATE/...
ISSUED AT 920 AM EST FRI FEB 27 2015

ONLY TWEAKED KIND WIND DIRECTION. STILL SOME UNCERTAINTY ON WHERE 
BROKEN CUMULUS FIELD WILL SET UP...SO LEFT FORECAST ALONE FOR NOW.

PREVIOUS DISCUSSION FOLLOWS...

VFR CONDITIONS EXPECTED THROUGHOUT THE FORECAST PERIOD.

HIGH PRESSURE WILL BUILD ACROSS THE OHIO VALLEY TODAY WITH PARTLY
CLOUDY SKIES. POCKETS OF STRATOCU CONTINUE TO DROP INTO CENTRAL
INDIANA WITH LOW LEVEL FLOW OFF LAKE MICHIGAN. DESPITE THE DRIER
AIR AND SUBSIDENCE OVERSPREADING THE REGION TODAY...COLD POOL
ALOFT AND PRESENCE OF 850MB THERMAL TROUGH BOTH SUPPORT RENEWED CU
DEVELOPMENT FOR THE AFTERNOON...ESPECIALLY AT KBMG AND KIND. 

AS CU SCATTERS OUT LATER THIS AFTERNOON...MID AND HIGH LEVEL
CLOUDS WILL INCREASE FROM THE SOUTHWEST FOR TONIGHT IN ADVANCE OF
A SYSTEM DEVELOPING OVER THE SOUTHERN PLAINS. SKIES WILL BECOME
OVERCAST AFTER MIDNIGHT AS CEILINGS LOWER TO 8-10KFT. NORTHWEST
WINDS AT 5-10KTS TODAY WILL EVENTUALLY BECOME LIGHT AND VARIABLE
OVERNIGHT.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
IND...NONE.

&&

$$

SYNOPSIS...JAS
NEAR TERM...JH
SHORT TERM...JAS
LONG TERM....RYAN
AVIATION...RYAN/50

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